Bovine Root Dentin as Alternative Substrate for RDA Testing

Objectives: The aim of this study was to evaluate bovine root dentin as an alternative substrate for the Radioactive Dentin Abrasive (RDA) test. The laboratory procedures followed the guidelines outlined in the ISO11609.
Methods: Different sets of human and bovine root dentin (n=8) slabs were prepared, irradiated and mounted in methyl methacrylate resin. Each substrate set was distributed into 4 groups: High, Medium and Low abrasive slurries; and Reference toothpaste (Crest Cavity Protection). They were brushed in a V8 brushing machine (Oral-B 40 toothbrushes, load of 150g) with the testing slurries (10g/50ml 0.5% carboxymethylcellulose) or toothpaste (25g/40ml water) for 1500 double-strokes. Specimens were also brushed with calcium-pyrophosphate (10g/50ml 0.5% carboxymethylcellulose), which was used as a reference group for RDA-value calculations (RDA 100). After brushing, the slurry was collected and analyzed in a liquid scintillation counter. The net counts per minute (CPM) values were divided by the weight of the slurry sample (CPM/g). The net CPM/g of the reference group was used in the calculation of RDA for the test groups. The experimental design was a modified Latin Square. Data was analyzed using one-way ANOVA and Student-Newman-Keuls tests. Student t-test was used for the comparison between substrates (all tests alpha=0.05).
Results: All the groups showed statistically significant differences. The high abrasivity slurry presented the highest RDA value for both substrates, followed by the medium- and low-abrasive slurries.
Conclusions: The bovine root dentine can be used as an alternative substrate for the RDA test.